Air conditioning apparatus



NOV. 24, 1936. I HUGGlNs 2,062,054

AIR CONDITIONING APPARATUS Filed April 26, 1935 24; fit g 16 250.

Li H INVENTOR h LEROY GA 1.5 Huaams 2 W 2.4-. 21,. ATTOR Y Y Patentedn... 24 193 6 NT OFFICE AIR CONDITIONING 'mnna'rus Leroy Gale Huggins,Wilkinsburg, Pat, assignor to Westinghouse Electric & Manufacturing ICompany, East Pitts of Pennsylvania burgh, Pa., a corporationApplication April 26,1935, Serial No. 18,295

-My invention relates to air conditioning apparatus, more particularlyto apparatus comprising a plurality of evaporators for cooling-aembodying my invention; and

stream of air, and it has for an object to provide improved apparatus. I

A further object is, in connection with an air conditioning systemcomprising a plurality of compressors or compressor-condenser units anda plurality of evaporators connected to each compressor, to equalize theloads on the com:

pressors and to cool the entire air stream at.

partial load.

A further object is to utilize standard developed apparatus. v

in series, and I connect each compressor to the firstevaporator inseries in one group and to the second or subsequent evaporator inanother. group. Thus, the higher load of the first ev'aporators, due tothe higher temperature'of the incoming air, is distributed among aplurality of condensing units. I

These and other objects are effected by my invention as will be apparentfrom the following description and claims taken in connection with theaccompanying drawing, forming a part of this application, in which: I

Fig. 1 is a diagrammatic view of apparatus Fig. 2 is a diagrammatic'view of a secondtembodiment of my invention.

Referring to the drawing in detail, I'show an air conditioning chamberIll, which is connected I to the enclosure to be air conditioned througha tan II and a duct l2. The fan ll eiiects circulation of the air to becooled through the chamber ill, the flow being from left toright in theembodiment illustrated in Fig. 1. v The fan may be located at anysuitable point in the air stream, and location at the outlet of thechamber l being but one example of a suitable location. Air to betreated is conveyed to the chamber through a duct l3 and may be eitherair withdrawn from the enclosure, outdoor air, or preferably a mixtureof both, as is well known in the art.

The chamber i0 contains a plurality of refrigerating evaporators forcooling the air and may, of course, contain any other desired airtreating elements. In the present embodiment, I show four evaporator-s,it to II, the evapor torsbeing arranged so that the air stream first esover the evaporators I4 and I5 in parallel for the first stage of aircooling,-'and the respective parallel portions then pass over theevaporators i6 and II, respectively, for the second stage of aircooling. In other words, the group of evapo- 5 rators i4 and I5 is inparallel with the group of evaporators i5 and I1 and the evaporatorsofeachgroup are in series with, each other with respect to air flow. vTheevaporators are preferably of the same capacity, for example, each 10evaporator may be a standard developed evaporatorof 6-ton or 72,000 13.t, u.' per hour capacity, or any other desired size. They may be of theusual cross-finned coil type. or of any other suitable type known in theart.

In the present'embodiment, I provide two compressor-condenser unit's i8and I! for withdrawing vaporized refrigerant from the evaporators andfor supplying liquid refrigerant thereto. Each unit includes, acompressor 20, a motor 2| ,ior driving the same, a'condenser 22 and aliquid receiver 23." Each unit maybe of standard design, having acapacity, for example, of 12 tons or 144,000 B. t. u. 'per'hour, servingtwo of the above-mentioned evaporators. While I 25 have shown separatecompressor condenser units, the invention is not so limited but may beema ployed where only separate compressors are used. I Inasmuch as theair passing over the evaporaters i4 and i5 is at higher temperature thanthe partially cooled air passing over the evaporators l6 and II, therefrigerating load on the former will be greater than the load on thelatter. As stated above, it is an object of the invention to imposeequal loads on the compressors or the compressor condenser units,inorder to provide thebest performance with apparatus embodying standarddeveloped elements, and also to cool the entire air stream at partialload. I accom- 40 plish this by connecting each compressor condenserunit to the first stage evaporator of one group and to a second stageevaporator of the other group. I j

Conduit means 24 connect the liquid receiver 23 of the unit it with theexpansion valves ll of the evaporators I! and i0, and conduit means 2!connect the outlet ends of said evaporators with the suction of thecompressor. Likewise, conduit means 2. connect the liquid receiver ofthe unit I! with expansion valves 25 of the evaporators H and I1 andconduit means'il connect the outlet ends of 'said' evaporators withtliesuction of the compressor. The expansion valves 7,

Y are preferably oi. the im knownas thermostatic. I

, expansion valves, which control the admission of -refrigerant inaccordance'with the superheat of the vaporized refrigerant dischargedfrom the evaporator, thereby serving to supply such quantity ofrefrigerant as canbe fully vaporized. Any

' other vsuitable form of pressure-reducing device or restrlctor may beused.

Thermostatic control mechanism is preferably provided for controllingoperation of the compressors. This mechanism includes a thermostat Tthat is responsive to the temperature of the air in the enclosure, andmay be positioned either in the enclosure or in the stream of airreturning from the enclosure to the chamber In through the .duct IS. Thethermostat 1! is provided with two switches 28 and 28 for controllingcircuits 3] and 32, respectively, which supply current to the motors .ofthe units I8 and I9, respectively. The thermostat and the switches arearranged so that the'switch 28 is first closed.

upon increase in temperature to a predetermined value at which it isdesired to maintain the enclosure, and so that the switch 28 is closedupon further increase to a slightly higher predetermined value. Theswitches open in reverse order upon decrease to slightly lowerrespective predetermined temperatures. stood that only the novelfeatures of control are Operation The operation of the above-describedapparalllustrated and that any other control feature may be employed.

tus is as follows: The fan H eflects circulation of air throughtheevaporators I4 to l1 in the chamber In in the manner described above.

When the air cooling load of the enclosure is sufilciently high torequire operation of both compressors, the temperature rises to a valuecausing the thermostat T to close both switches.

Ene'rgization of both circuits and operation of by the evaporators H andI1, successively. As

each unit serves one evaporator in in the first stage of air cooling andone evaporator in the second stage of air cooling, it will be apparentthat the loads on the two units will be equal.

When the temperature decreases to the lower value indicating thatoperation of one compressor will supply sufilcient refrigeration, theswitch 28 is opened by the thermostat T to shut down the unit l8. Theunit 18 continues to operate to serve the evaporators l4 and H. In thiscase, both portions of the air stream are cooled, one by the evaporatorl4 and the other by the evaporator I'I. Both evaporators are subject tothe temperature of the incoming air and are subject to equal loads.However, the temperature is now lower than when operation of both unitsis .required, so that the total load on the two evapthe unit I9 todiscontinue further cooling of the air. Upon subsequent increase intempera- It is to beunder- One half.

ture, the thermostat first closes the switch is to effect operation ofthe unit l8, and upon further increase in temperature, it closestheswitch 28 to efiectoperation of the unit l8.

In Fig. 2, I show anembodiment of my invention in which a greater numberof evaporators are required to supply the cooling load. Three groups ofevaporators are arranged for cooling the air in three parallel portions,each group including two evaporators in series with respect to air fiow,as in Fig. 1. In this case, the conduit means Ha and 25a connectthe'unit l8 to a third evaporator 33 in the first stage of air cooling of athird parallel portion of the air stream, as well as to the evaporatorsl5 and I8. Conduit means 26a and 21a connect the unit N to a thirdevaporator 84 disposed in the second stage of air cooling, as well asthe evaporators l4 and H. In this case, the loads on the compressorcondenser units are only partially balanced; however, the difference inload is only one-third of that which would be obtained if all threefirst stage evaporators were connected to one unit and the second stageevaporators connected to the other unit. The difference in loads isreduced to a suificiently low value to be unobjectionable.

From the above description, it will be seen that I have provided anarrangement in which the evaporators are so arranged as to equalize orsubstantially balance the loads on the compressors or compressorcondenser units to which they are connected, and so that all portions ofair stream are cooled when only one unit is opcrating. This arrangementgreatly facilitates is f the use of developed apparatus of standardcapacity.

While I'have shown my invention in two forms,

it will be obvious to those skilled in the art that it is not solimited, butis susceptible of various other changes and modifications,without departing from the spirit thereof, and I deslre,-

therefore, that only such limitations shall be placed thereupon as areimposed by the prior art or as are specifically set forth in the apendedclaims.

What I claim is: 1. In air cooling apparatus, the combination of aplurality of compressors, a plurality of evapoparallel portions of theair stream.

2. In air cooling apparatus, the combination of a" plurality of groupsof evaporators, means for conveying air over said groups in parallel,the evaporators in each group being arranged to cool the air insuccessive stages, a plurality of conipressors, each compressor beingconnected to at least one evaporator in each stage of air cooling and ineach parallel portion of the air stream.

3. In air cooling apparatus, the combination of a plurality ofcompressors including first and second compressors, a plurality ofevaporators connected to each compressor, means for circulating air oversaid evaporators, said evaporators and the circulating means beingarranged so that one portion of the air stream is first cooled by anevaporator of the first compressor and then by an evaporator of thesecond compressor and another parallel portion of thealr stream is first55 connected to evaporator elements in a plurality of 1 cooled by anevaporator of said second compressor and then by an evaporator of acompressor other than the second compressor.

, 4. In air cooling apparatus, the combination of a plurality ofevaporators, means for convey-- ing air oversaid evaporators, saidevaporators being arranged in-a plurality of groups that are in parallelwith respect to air flow, each group comprising a first and a secondevaporator over which the air flows in the order named, and a pluralityof compressors each connected to the first evaporator of at least onegroup and to the second evaporator of at least one other group.

5. In air cooling apparatus, the combination of a plurality ofcompressors, a first and a sec ond evaporator connected to eachcompressor, means for circulating air over said evaporators, saidevaporators and the circulating means being arranged so thatair fiowsover a first evaporator and then over a second evaporator and so thateach first evaporator is in series with the second evaporator of anothercompressor and in parallel with the first evaporator of anothercompressor with respect to air flow.

6. In aircooling apparatus, the combination of a plurality ofcompressors, a plurality of evaporators connected to each compressor,means for circulating air over said evaporators, said evaporators andthe circulating means being arranged so that each parallel portion ofthe air stream is cooled in successive stages by evaporators of aplurality of compressors and so that at least two evaporators of eachcompressor are in different air cooling stages.

7. In air cooling apparatus, the combination of a plurality ofevaporators arranged in groups means for circulating air over theevaporators,

the several groups being arranged in parallel andthe evaporators in eachgroup being arranged in series with respect to air fiow, a plurality ofcompressors for said evaporators, each compressor being connected to aplurality of evaporators disposed in different groups and in difierentpositions in the order of air flow.

LEROY GALE'IIUGGINS.

